1. Field of the Invention
The invention provides nucleotide sequences encoding the gpm gene and fermentation processes for the preparation of amino acids, especially L-lysine, using corynebacteria in which the gpm gene is amplified.
2. Background Information
Amino acids, especially L-lysine, are used in human medicine and in the pharmaceutical industry, but especially in animal nutrition.
It is known that amino acids are prepared by the fermentation of strains of corynebacteria, especially Corynebacterium glutamicum. Because of its great importance, attempts are constantly being made to improve the preparative processes. Improvements to the processes may relate to measures involving the fermentation technology, for example, stirring and oxygen supply, or the composition of the nutrient media, for example, the sugar concentration during fermentation, or the work-up to the product form, for example, by ion exchange chromatography, or the intrinsic productivity characteristics of the microorganism itself.
The productivity characteristics of these microorganisms are improved by using methods of mutagenesis, selection and mutant choice to give strains which are resistant to antimetabolites, for example, the lysine analogue S-(2-aminoethyl)cysteine, or auxotrophic for metabolites important in regulation, and produce L-lysine.
Methods of recombinant DNA technology have also been used for some years to improve amino acid-producing strains of Corynebacterium by amplifying individual amino acid biosynthesis genes and studying the effect on amino acid production. Review articles on this subject have been published inter alia by Kinoshita (“Glutamic Acid Bacteria”, in: Biology of Industrial Microorganisms, Demain and Solomon (Eds.), Benjamin Cummings, London, UK, 1985, 115-142), Hilliger (BioTec 2, 40-44 (1991)), Eggeling (Amino Acids 6, 261-272 (1994)), Jetten and Sinskey (Critical Reviews in Biotechnology 15, 73-103 (1995)) and Sahm et al. (Annals of the New York Academy of Science 782, 25-39 (1996)).